2021 Fiscal Year Annual Research Report
Hunting physics beyond General Relativity with gravitational waves
| Project/Area Number |
21F21318
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| Allocation Type | Single-year Grants |
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| Research Institution | Kyoto University |
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Principal Investigator |
向山 信治 京都大学, 基礎物理学研究所, 教授 (40396809)
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| Co-Investigator(Kenkyū-buntansha) |
DI FILIPPO FRANCESCO 京都大学, 基礎物理学研究所, 外国人特別研究員
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| Project Period (FY) |
2021-11-18 – 2024-03-31
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| Keywords | gravitation / cosmology / gravitational waves |
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| Outline of Annual Research Achievements |
The first achievement obtained regards the classification of non-singular black holes in Lorentz violating theories of gravity. The results are summarized in the paper "Geodesically complete black holes in Lorentz-violating gravity". In this paper, we discuss the significance of trapping horizons in frameworks with modified dispersion relations. This leads to the introduction of the notion of universally marginally trapped surfaces, as the direct generalization of marginally trapped surfaces for frameworks with infinite signal velocities (Horava-like frameworks), which then allows us to define universal trapping horizons.
In the paper "On the inner horizon instability of non-singular black holes" we discuss the problem of mass inflation that makes the core of regular black holes unstable.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Currently there are two separate projects that are close to the completion.
The first project introduces a regular black hole geometry that, contrary to every other example present in the literature, does not suffer from the mass inflation instability. This feature makes such a geometry an interesting candidate as an effective description of black holes beyond
general relativity.
In a second project, we are studying the stability of quasinormal modes when a small perturbation is added to the background potential. While the quasinormal modes spectrum is unstable, we have shown that the physical quasinormal modes that can be extracted from a gravitational waves detections are stable. This feature is very important in light of current and future black holes spectroscopy observations.
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| Strategy for Future Research Activity |
We will try to describe a dynamical process leading to the formation of the regular black holes geometries we have just introduced starting from one of the other regular black holes geometries considered in the literature. We will also continue working on the interplay between the quasinormal modes spectrum and possible observation of physics beyond general relativity.
Parallelly, we plan to study Hawking radiation for a spacetime describing a gravitational collapse that does not lead to the formation of a singularity.
Other projects that will be addressed in the future include the investigation of some aspects relative to the information loss problem, the extension of the BMS symmetry in non-asymptotically flat spacetimes, and the causality of theory with superluminal propagation speed.
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Research Products
(5 results)
